Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Implantable prosthesis – Hollow or tubular part or organ
Reexamination Certificate
2001-04-18
2004-04-06
McDermott, Corrine (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Implantable prosthesis
Hollow or tubular part or organ
C604S008000, C604S096010
Reexamination Certificate
active
06716252
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a stent configured for insertion into a lumen or body cavity of a subject.
BACKGROUND OF THE INVENTION
Conventionally, several types of thermal treatment systems have been proposed to treat certain pathologic conditions of the body by heating or thermally ablating targeted tissue. These thermal treatment systems have used various heating sources to generate the heat necessary to treat or ablate the targeted tissue. For example, laser, microwave, and radio-frequency (RF) energy sources have been proposed to produce the heat which is then directed to the targeted tissue in or around the selected body cavity. Thermal treatment systems have been used to thermally ablate the prostate (as well as other organs, body cavities, and/or natural lumens).
One particularly successful thermal ablation system is directed to thermally ablating the prostate by a thermocoagulation process. This thermal ablation system employs a closed loop liquid or water-induced thermotherapy (WIT) system which heats liquid, typically water, external to the body and then directs the circulating heated water into a treatment catheter which is inserted through the penile meatus and held in position in the subject undergoing treatment to expose localized tissue to ablation temperatures. The treatment catheter includes an upper end portion which, in operation, is anchored against the bladder neck and an inflatable treatment segment which is held relative to the anchored upper end portion such that it resides along the desired treatment region of the prostate. In operation, the treatment segment expands, in response to the captured circulating fluid traveling therethrough, to press against the localized or targeted tissue in the prostate to expose the tissue to increased temperatures associated with the circulating liquid, thereby thermally ablating the tissue at the treatment site. In addition, the pressurized contact can reduce the heat sink effect attributed to blood circulation in the body, thus enhancing the depth penetration of the heat introduced by the inflatable treatment segment into the prostatic tissue.
As an acceptable alternative to surgery (transurethral resection of the prostate (TURP)), the use of WIT (water-induced thermotherapy) has been shown to be particularly suitable for the treatment of BPH (benign prostatic hyperplasia). Generally stated, the term “BPH” refers to a condition wherein the prostate gland enlarges and the prostatic tissue increases in density which can, unfortunately, tend to close off the urinary drainage path. This condition typically occurs in men as they age due to the physiological changes of the prostatic tissue (and bladder muscles) over time. To enlarge the opening in the prostatic urethra (without requiring surgical incision and removal of tissue), the circulating hot water is directed through the treatment catheter, which is inserted into the penile meatus up through the penile urethra and into the prostate as described above. The treatment segment expands with the hot water held therein to press the inflated treatment segment against the prostate, which then conductively heats and thermally ablates the prostatic tissue. The circulating water is typically heated to a temperature of about 60-62° C. and the targeted tissue is thermally treated for a period of about 45 minutes to locally kill the tissue proximate the urinary drainage passage in the prostate and thereby enlarge the urinary passage through the prostate.
Subsequent to the delivery of the thermal ablation treatment, the treated tissue in the prostate undergoes a healing process. Initially, the ablated tissue can expand or swell due to inflammation or edema which can undesirably block or obstruct the prostatic urethra. Further, during the healing period, portions of the treated tissue can slough off and create an undesirable and unduly limited opening size. This post-ablation treatment opening size can be positively influenced by “molding” the ablated tissue during the healing cycle to contour the tissue about a catheter or stent held thereat. Therefore, to facilitate proper healing and to enhance the efficacy of the ablation therapy, either the treatment catheter is left in the subject for a period of time and/or a post treatment catheter, such as a conventional Foley catheter, is positioned in the subject. However, the amount of time that the treatment or post-treatment catheter must reside in the subject can be from 2-14 days, or even longer. Therefore, it is desirable to configure the post-treatment catheter in a minimally invasive manner to allow normal operation of the sphincter, remove the need for the use of an incontinence bag, and reduce the inconvenience or discomfort to the user.
Conventionally, Foley-type catheters with bladder anchoring balloons located on an upper end portion have been used as post-treatment catheters to allow the thermally ablated tissue to mold around the catheter perimeter during the initial healing phase. While these type catheters allow the post-treatment catheter to be securely positioned relative to the bladder neck of the subject, natural operation of the sphincter is inhibited, and the configuration is relatively cumbersome (in position it extends through the penile urethra) and can be considered unduly invasive by the user and may increase the risk of urinary tract infection (UTI) when in position in the subject (particularly, when used for extended periods of time). Other post-treatment catheter configurations (also known as “indwelling catheters” and “stents”) have also been proposed; however, some of the catheter types can inhibit the ability to flush out blood clots which may exist from the therapy, and others are undesirably invasive to the user and/or prevent or inhibit the natural operation of the sphincter. Still others are not able to be properly located within the prostatic cavity about the treatment region and/or are unable to retain their desired position in the prostate over time. Still others can, during prolonged use, promote muscle atrophy and/or localized tissue necrosis.
Examples of known post-treatment catheters or stents are described in U.S. Pat. No. 5,916,195 to Eshel et al., U.S. Pat. Nos. 5,876,417 and 5,766,209 to Devonec et al., and U.S. Pat. No. 3,811,450 to Lord. However, there remains a need to provide improved and/or minimally invasive post-treatment catheters or stents which are cost effective and can be positioned and located in the prostate proximate the treated tissue during the post thermal ablation process or healing cycle (which can contour or mold the tissue) and which can be easily removed at the appropriate time.
OBJECTS AND SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a stent which is suitable for inhibiting post thermal ablation obstruction in the prostate and which is configured in a minimally invasive manner to the wearer.
It is another object of the present invention to provide a stent which can be inserted through the penile meatus and penile urethra to be positioned in the prostatic urethra and held in a desired position relative to the thermally treated tissue during prolonged use.
It is yet another object of the present invention to provide a stent which can be locally anchored in a relatively stable manner in the prostate such that longitudinal migration or movement toward or away from the bladder is inhibited.
It is another object of the present invention to provide a device which can inhibit obstruction in the prostatic urethra to keep the urinary drainage path open such that the subject is able to discharge urine in a normal manner.
It is an additional object of the present invention to provide a way to monitor the movement of catheters and/or to provide improved ways to determine that the integrity of the inflation system is intact.
It is another object of the present invention to provide improved stents which are able to inhibit obstruction in a lumen or cavity.
These and other objects are satisfied by the present inv
Cioanta Iulian
Klein Richard Barry
Lazarovitz Jacob
Ganz Bradley M.
Ganz Law P.C.
McDermott Corrine
Stewart Alvin
WIT IP Corporation
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